A man was stabbed and robbed of his bicycle on a City Hall subway platform early this morning, according to police.

The 31-year-old victim and his alleged assailant boarded the Market-Frankford El at separate stops, and as they exited the El at 15th Street around 12:45 a.m., the men got into an argument of an unknown nature, police said.

As the victim was trying to lift his mountain bicycle over the turnstile, the assailant charged at him with a knife and cut the victim's chest, causing several small lacerations, police said.

The knife-wielding man then grabbed the victim's bike and tried to run with it, but the bicycle was too cumbersome and the man dropped it and fled through a City Hall exit, according to police.

The offender has not yet been identified but police described him as a 6-foot-2 Hispanic man with a gray-and-black beard and an all-gray hoodie.

The victim has been listed in stable condition.